Transactions are approved/not approved by the card-issuing bank; not Equip-Bid. Equip-Bid works with a processing network, it provides varying reasons for their decline responses. Sometimes they can be specific and provide responses such as Activity Limit Exceeded or Insufficient Funds. Other times their responses can be very generic such as Do Not Honor or Not Approved. The best way to help understand what is causing the non-approval would be to have you, the customer contacts your card issuing bank for further clarification on why the card is being declined.
Keep in mind that debit cards usually have a daily spending limit set by your bank. If your bank has a $1,000 limit and you are trying to spend $1,500 (even though you may have more than this in your bank account) it will not go through. You can either call your bank and ask them to extend your spend limit for the day or use another credit card or payment type.